


Cat Got Your Tongue?

by Fae_Ryn



Category: Undertail - Fandom, Undertale
Genre: Also tooth-rotting fluff, Bad Puns, Be sure your partners are comfortable alright, I'm a sinner so sin with me dang it, I'm big on consent, Multi, Oral Sex, Penis In Vagina Sex, Porn Without Plot, Probably some cursing I forget, Reader and Sans are in an established relationship, Reader gets to eat Sans out, Reader has a penis because they can, Reader has no genitalia unless they summon something, Reader is big on consent, Ridiculous jokes because Sans, Sans has a vagina because he can, Sans is lazy but that's not going to stop him, The world is your mcfreakin' oyster, Their gender/sex/species is really entirely up to you, Writing Sans gives the grammar lover in me nothing but sorrow, go wild - Freeform, reader isn't gendered
Language: English
Status: Completed
Published: 2016-08-31
Updated: 2016-08-31
Packaged: 2018-08-12 03:35:03
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,267
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7918954
Author URL: https://archiveofourown.org/users/Fae_Ryn/pseuds/Fae_Ryn
Summary: <blockquote class="userstuff">
              <p>You and Sans have the house to yourselves, and Sans wants to try something new. Well, nobody can say you're opposed to eating out.</p>
<p>Sans has a vagina, Reader has a penis, Sans still identifies as male, Reader is completely ambiguous. Enjoy the sin!</p>
            </blockquote>





	Cat Got Your Tongue?

As is the usual Sans way, sex starts slowly. One minute you’re cuddling on his bed, watching dumb television and trading dumber jokes, the next you’re making out, tongues languidly twining together, arms wrapped loosely around waists. He breaks off the kiss to bite your neck just hard enough to leave a mark.

 

“Paps’ gonna scold you for ‘hurting your mate’ again,” you laugh, nuzzling his cheek as he presses kisses down your neck and over your collarbones.

 

“Well my mate enjoys it,” he counters.

 

You groan out your agreement as he suckles your neck. His hands move from your waist up to your back, kneading the soft flesh along the way. He helps you pull your shirt off before his hands eat up the feeling of your skin once more.

 

“Mmm, I love this stuff,” he says, pulling back to watch his fingers pressing into your skin.

 

You laugh, fingers finding their way underneath his shirt. “Yeah, I kinda figured.”

 

You brush your fingers over his ribs before pulling him closer, his hands leaving your sides to circle your waist again. You trace the little dips and bumps of his spine as he bites your lip just hard enough to cause momentary pain. With a growl, you push him down and straddle him.

 

“Ahhhh,” he ‘screams’, throwing his hands up. “I’ve been caught. Oh dear. Whatever shall I do.”

 

You roll your eyes and remove his shirt while his arms are raised. “You do realize I’m trying to seduce you, right?”

 

“Well, maybe you’re succeeding,” he says with a wink.

 

You grin at the challenge. “Oh, only ‘maybe’, huh?”

 

You lean over and nip playfully at his vertebrae, listening as his breathing quickens in response. You run your tongue over the sensitive bones and just enjoy the sounds that your actions earn you. Knowing his pelvis is an especially pleasurable area but unable to reach down, you slide your knee in between his legs.

 

Rubbing between his legs as best you can, you return your attentions to his neck. As you give attention to his bones you feel something forming against your leg. Through the arousal it takes you a moment before you realize that whatever it is that’s forming isn’t in the usual spot.

 

You pause your ministrations to look down and verify what you’re feeling. Pressed against your knee is an already damp pussy, glowing bright blue through his shorts. You glance back up at Sans to see him grinning back at you in self-satisfaction.

 

“What, cat got your tongue?” he asks.

 

You groan dramatically. “That was only barely a pun.”

 

“Hey, it works as long as you’re smiling.”

 

You almost shoot a retort back at him before you realize there are better ways to get back at your pun loving boyfriend. You give him a grin with your eyes half-lidded, slowly crawling backwards until your face is hovering just over his conjured opening. Sans follows you with his gaze, propping himself up onto his elbows. He doesn’t stop you as you slide your hands up and over his pelvis to his shorts, so you shimmy them off to reveal his slit.

 

You’re venturing into unfamiliar territory but at this point you’re too curious to stop. You glance up at Sans, finding his eyes watching you carefully. When you pause he meets your eyes. “What, you too pussy?”

 

“I’d say you’re a dick, but you seem to be lacking one,” you shoot back. After Sans has stopped laughing, you say, “But seriously, you okay with this? I mean we’ve never tried this before.”

 

“Don’t have to if ya don’t want to,” Sans says, shrugging.

 

You groan in exasperation. You love Sans to death but honestly. The man should really start thinking of himself a bit more. “Sans. That wasn’t what I was asking and you know it.”

 

“I wouldn’t’ve made it if I wasn’t okay with it,” he reminds you.

 

“Well, then,” you say, licking your lips for dramatic effect, “Bone appetite.”

 

Sans’s laughter is quickly choked off as you lean forward, licking a long, slow path down his lower lips. You note that there’s no flavor to it, just a faint tingle across your tongue as you flick the little nub at the top. Sans makes another strangled noise as you sink just the tip of your tongue between his folds. You gently take the folds of his inner lips between your teeth and let it slip past, careful to avoid hurting him. Another long, slow stripe up his slit, taking notice of the increased wetness. You look up, ready to ask him if it’s alright to take it further, and the look on his face is all the answer you need. He’s blushing heavily, face painted bright blue as the tip of his tongue peeks out between his parted teeth. His eye sockets are closed, breathing heavy.

 

You feel a grin stretching your lips as you dive in. Your tongue traces the inner walls of Sans’ vagina as he groans, legs twitching on either side of your head. A quick glance up shows you that his eye sockets are stretched open wide, teeth parted in apparent surprise. You give him a wink as you keep going. Sans’ laugh is breathy and just right, sending a wave of arousal to your own nether regions, and when you moan in response his hips jerk upwards, your nose colliding with his clit and causing him to yip. When you stop to ask if everything’s alright he very nearly whines at the loss of contact.

 

Figuring you can’t be messing up that badly if he’s enjoying himself, you resume your ministrations. You curl your tongue inside of him, getting as far inside as you can. Sans’ breathing becomes faster and harder as one hand winds its way into your hair to ground himself. Before long your tongue is getting tired even as Sans’ noises are increasing in both frequency and pitch. You give your tongue one last curl before pulling out, replacing it with two of your fingers. You move upwards, suckling at his clit as you pump your fingers in and out of his pussy. You soon find yourself adding a third finger, Sans’ walls stretching to accommodate. As your lips and tongue play with his clit your fingers press into his sweet spot. You try to move back as he jerks into your movement only to be stopped by a firm hand on the back of your head. As his hips keep moving upwards, little whimpers and moans coming from his throat, walls tightening around your fingers, you hum against his clit. That has him tipping over the edge, crying your name loud enough that you wonder if the neighbors will hear.

 

You let him ride out the aftershocks, his pussy pulsing around your fingers. When his hand slides off of your head you come up for air. Sans looks wrecked, face flushed and mouth wide open as he pants for air.

 

Despite being seriously in need of some attention yourself you crawl along the bed and flop down beside him, nuzzling his skull. “So, how’d I do?”

 

“Good, definitely good,” he says, breathing hard.

 

You chuckle. “Glad to hear it.”

 

It’s a few minutes later, Sans’ breathing almost down to its usual pace, before he speaks again. “I, uh, think I’m up for round two… If you’re interested.”

 

“Kinda tired, sorry,” you say, mildly surprised that he’d ask you to do it again so soon.

 

You start in surprise, eyes snapping open - when had you closed them? - as Sans clambers on top of you, grinning down at you. “Heh, I know I’m lazy, but I can do some a the work ya know.”

 

“But how’re- Oh,” you breathe, noticing that his vagina is still in place.

 

“Oh,” he echoes. “Unless you don’t want to?”

 

“I, uh, you know, um,” you stammer, face heating up. “I’d l-love to but, uh…”

 

Sans raises a skeptical brow. “You’re tellin’ me you’ve never tried making a dick before?”

 

You groan in embarrassment, hiding your face. “Alright, so I have.”

 

“And?” he drawls.

 

“And I enjoyed it,” you huff. “But seriously, I’ve never done this before. Solo, sure…”

 

“No time like the present for unwrappin’ this gift,” he says with a wink.

 

“You’re a dork,” you groan. Sans chuckles, waiting. You take a deep breath, concentrating on the magic that’s a little more familiar than you’d like to admit. Your magic jumps at your command, your body eager for relief. Within a few moments there’s a not so subtle glow from your pants as your cock pushes past the hem of your underwear.

 

As Sans glances down in surprise, you stutter out an explanation. “I, uh figured, since, you know, yours is-”

 

Sans interrupts you by laughing. “‘S fine, don’t worry ‘bout it. Just wonderin’ if yours was always like that.”

 

“Not when I was by myself,” you admit.

 

Sans’ grin is damn near predatory as he leans closer to whisper in your ear. “Didja jack off to the thought a me?”

 

Your face is hot enough to fry an egg as you stutter your - admittedly false - denial. Sans only manages to look smug for a second or two before he’s laughing, shoulders shaking in mirth. You groan and shove his shoulder weakly.

 

“Asshole,” you mutter.

 

“Ahh, sorry, sorry,” Sans says, leaning in for a kiss. You lean away and his teeth hit your cheek instead. “Aw, c’mon darlin’. I’m sorry.”

 

You grumble but this time let the kiss land. Slowly but surely Sans makes you forget why you were irritated, his tongue working magic on yours, grinding his vagina down onto your erection. You buck up into him as you feel the heat of it even through the cloth still holding you back.

 

“Sans so help me god-” you groan, grasping his hips to pull him further onto you, wishing you could make your clothes vanish so you could slip into the hot, wet warmth only millimeters away.

 

“I gotcha,” he says breathily, sliding off of you on unsteady legs so that you can kick off the last of your clothes. The second your clothes hit the floor he’s back on top of you. You gasp as he’s finally pressed flush against you - it’s better than you’d dreamed, hot and wet against your cock. He slides over you slickly as he humps you and lets out a moan thick with lust.

 

“I- Sans, I need- please!” you groan, hips bucking up against your will.

 

Sans leans back, rising just enough to grab your dick and position it below his aching pussy. He pushes it in slowly, obviously relishing the low, primal sounds coming out of your throat as your length slides inside. It’s wonderfully tight, squeezing you with slick, wet velvet walls. Your fingers grasp the sheets as you hilt inside of him. You so badly want to start moving - to hear those broken moans that make you go crazy, to feel this amazing sensation sliding across your length as you pleasure him - but you hold yourself back, not wanting to hurt him.

 

Your patience is rewarded a short moment later as Sans finally starts moving. His movements are slow and uncertain at first, gaining confidence as he goes. You start moving with him, meeting his downward thrusts with your own. Without conscious thought your hands find his hips, pulling him down to meet you as hard as you can before helping him move up only to slam down again. You’re hitting something deep inside that has his tongue lolling out, whimpers making it past his teeth every time you hilt.

 

A stream of broken words come from his mouth as you find a pace you can work together, goading you on by whimpering your name amid compliments and pleas for ‘More, oh stars more, please!’

 

“Sanss,” you whimper, feeling yourself moving closer to the edge.

 

He moans loudly in response, soft walls tightening around you and causing your strokes to falter. You grit your teeth, breathing heavy. You keep moving, rubbing the tip of your cock against a spot that has him jerking his hips down hard, legs shuddering at your sides. You’re so close, too close, holding your breath as you force yourself not to finish before he does.

 

You’re fighting a losing battle when Sans cries out, arms coming around your waist and pulling you in as far as you’ll go as his cunt squeezes your cock impossibly harder. He’s whimpering broken sounds that might be your name and that’s what does it - your cock twitches as you come inside of him, shouting his name.

 

When his pussy finally stops spasming around you, the last of your come spurting out, he collapses on top of you, shuddering, magic dissipating almost instantly. You’re both gasping, flushed messes, pressing sloppy kisses to whatever you can reach of the other’s body. You’re pretty sure you couldn’t move even if you wanted to and Sans isn’t in much better shape.

 

Many minutes later, you’re breathing steadily again, Sans finally having slipped off to one side. His head is pillowed on your chest, your  arm wrapped loosely around his shoulder.

 

“That was nice,” you say tiredly.

 

“It was a bone-a-fide good time,” Sans agrees.

 

“When I find the energy I’m gonna smack you for that.”

 

“Nah, you’re not.”

 

“Mphhh. You could’ve played along.”

 

Sans chuckles, turning his head to place a kiss on your forehead. “We should do that more often.”

 

“Sure thing, bonefriend.”

 

Sans laughs again. “Hey, sweetheart?”

 

“Yeah Sans?”

 

“Love ya.”

  
“I love you too, you dork.”

**Author's Note:**

> I wrote this for a friend who probably wouldn't appreciate me gifting it to them but you know who you are. We can all be sinners together. 
> 
> Also in case anybody was wondering the title of this one-shot on google docs was 'Exercising Out My Kinks' because I've lost control of my life.
> 
> And yes, the title is a pun.


End file.
